Method and apparatus for expanding tubes



P 8, 1954 w. E. STARY 2,690,205

METHOD AND APPARATUS FOR EXPANDING TUBES Filed July 10, 1950 7 Sheets$heet l /5 j I /2 l7 /6 I8 20 F/s. I.

W A50! V/ 2-l I v I INVENTOR.

Sept. 28, 1954 w, sTARY 2,690,205

METHOD AND APPARATUS FOR EXPANDING TUBES Filed July 10, 1950 v 7 Sheets-Sheet 3 IN VEN TOR.

P 8, 1954 w. E. STARY 2,690,205

METHOD AND APPARATUS FOR EXPANDING TUBES Filed July 10, 1950 7 Sheets-Sheet 4 IF 73 F/@. /0. 63

1.s 22-2 m F 6. ll.

L5 22"] I I INVENTOR. 'H TIM-1 WM 6 M FIG/2.

Sept 28, 1954 w. E. STARY 2,690,205

METHOD AND APPARATUS FOR EXPANDING TUBES Filed July 10, 1950 7 Sheets-Sheet 5 I F 50/, F3] C501 F35 L 33 7/ l. A P/5 l L s 322 INVENTOR.

-+;@- A wzzz aja Sept. 28, 1954 w, E, STARY 2,690,205

METHOD AND APPARATUS FOR EXPANDING TUBES Filed July 1o,195o 7 Sheets-Sheet e Sept. 28, 1954 w. E. STARY 2,690,205

METHOD AND APPARATUS FOR EXPANDING TUBES Filed July 10, 1950 '2 Sheets-Sheet 7 IN V EN TOR.

Patented Sept. 28, 1954 [TED STATES ATENT OFFICE METHOD AND APPARATUS FOR EXPANDING TUBES 21 Claims.

This invention relates to manufacture in which measured quantities of work are performed and automatically controlled, in which one function of the work to be done is the displacement of a tool performing the work or the displacement of the element upon which the work is performed.

An example of such measured quantities of work is drilling holes a constant depth in parts varying in thickness and varying so that the surface in which the drill enters varies in distance from the surface of the support backing-up the drilling force.

Another example is moving an element upon which work is done, relative to the tool, so that a preselected pattern of work can be repeated at preselected intervals.

Another example is machining grooves of a fixed cross-section in a series of parts which vary in diameter.

A further example is rolling and expanding tubular elements in the tube-holes of external elements with which they are to be assembled, when the clearance between the tubes and their mating assembly member varies, and when the tube-joints are to be made to a uniform tightness, such as the tube-joints in a heat-exchanger.

One of the primary objects of this invention is to provide a method of accurately detecting when the quantity of work to be measured is to start.

Another object of this invention is to provide a method of measuring and controlling the movement of the tool so that said uniform quantities of work are produced.

A further object of this invention is to provide machines for performing the work to accomplish the objectives of the method mentioned above, so as to do the work precisely, quickly and automatically.

The preferred method of accomplishing these objectives is that which rapidly advances the tool to the position where the measured quantity of work is to be commenced and then continues the tool advance at a rate suitable for the work to be performed.

These and other objectives and advantages of this invention will become apparent from the following description when taken in connection with the accompanying drawings, in which:

Fig. 1 is a side elevation of a machine for drilling holes.

Fig. 2 shows an arrangement of hydraulic elements which may be used to control the machine shown in Fig. 1, to drill holes a constant depth in a series of parts varying in their X dimension.

Fig. 3 shows a schematic electrical diagram for operating and controlling the hydraulic equipment shown in Fig. 2.

Fig. 4 shows parts of a mechanism for moving work through a punch-press while a series of equally-spaced holes are punched.

Fig. 5 shows an arrangement of hydraulic elements which may be used to control the moving of the work shown in Fig. 4.

Fig. 6 shows a schematic electrical diagram for operating and controlling the hydraulic equipment shown in Fig. 5.

Fig. '7 shows an arrangement of machine-parts for machining grooves in a tubular element.

Fig. 8 relates to tube expanding. It shows a section through the assembly of a tube and its tube-hole with the expanding tool in the tube, taken along the line 8-8 of Fig. 10, before the tube starts to expand.

Fig. 9 is the same section shown in Fig. 8 showing, to a slightly exaggerated degree, the shape and condition of the tube when the several angularly spaced areas on the outer surface of the tube first make firm contact with the tube-hole.

Fig. 10 is the side elevation of a machine for driving the expanding tool to expand tubes into firm engagement with an external member with which the tubes are to be assembled.

. Fig. 11 shows an arrangement of hydraulic elements which may be used to control the machine shown in Fig. 10.

Fig. 12 shows a schematic electrical diagram for operating and controlling the hydraulic equipment shown in Fig. 11.

Fig. 13 is a section through the machine shown in Fig. 10 in the direction of the line l3it.

Fig. 14 is a section through the machine shown in Fig. 10 in the direction of the line l lhi.

Fig. 15 shows another combination of hydraulic elements which may be used to operate the machine shown in Fig. 10.

Fig. 16 shows a schematic electrical diagram for operating and controlling the hydraulic equipment shown in Fig. 15.

'ments for controlling and operating the machine shown in Fig. 17.

Fig. 19 shows a schematic electrical diagram for operating and controlling the hydraulic equipment shown in Fig. 18.

Fig. 20 shows a side elevation of an alternate combination of mechanism to drive the selffeeding type of expanding tool and to perform the expanding operation by the method described in this invention.

Fig. 21 shows a side elevation of an alternate combination of mechanism to drive the expanding tool by rotating its roll-cage and to perform the expanding operation by the method described in this invention.

In current manufacturing practices there are many operations which require controlling of preselected measured quantities of work, and in which the magnitude of the measured quantities are changed from time to time. shown and described are indicative of the types of manufacturing operations which can advantageously use this invention.

The drilling machine shown in Fig. 1 drills holes in a series of parts H which vary in their X dimension. The holes drilled by drill [2 are to be a constant depth C in each of the parts ll. Since X varies, the approach-distance to commence the drilling varies from one part to the next.

The bracket l3 which is a part of the frame l4 backs-up the work ll while the hole is being drilled. The power unit l5 supplies the rotating force to drive the drill l2 with said force being transmitted through the spindle l6. Spindle I6 is guided in the journal in the bracket i1 attached to the frame l4. Power unit is in slidable engagement with the frame M in such a manner that the frame [4 resists the reactive rotation of the power-unit l5 when the drill I2 is doing work.

The axial force applied to the drill I2 is supplied by the hydraulic cylinder |9 through the piston rod l8 connected to the drive-unit IS. The bracket attached to the frame l4 supports the hydraulic cylinder [9, and the bracket contains a gland and guide-bearing for the piston rod l8.

From this description we see that movement of the drill l2 is proportional to the change in volume of the hydraulic fluid in front or rear of the piston in the cylinder 19.

The hydraulic fluid is pumped from the tank Ti, in Fig. 2, to the four-way valve Fl by the pump P2. Valve Fl is solenoid operated by solenoid Sol Fl, with the pressure-flow from line Ll to line l3 when solenoid Sol Fl is deenergized. Valve V2 is normally open and thus the drill is normally held in a retracted position.

The cycle is started by momentarily closing the push-button switch Bl in Fig. 3. The control-cylinder MI which measures the depth of drilling is discharged and the normally-open contact LSl-l in limit switch LSl is held closed. Thus when the push-button-Bl is closed, current flows through coil Rl-C on relay Rl and energizes said relay.

Contact Rl-l closes and holds the relay RI closed. Contacts Rl-Z closes andenergizes the solenoid Sol Fl thus actuatingfour-way valve Fl. Now the pressure-flow from the pump P2 goes through line Ll to line L2. The solenoidoperated valve V! is normally openand the hydraulic fluid flows through valve Vl, on through lines L4 and L5 to the cylinder IS. AS the piston in cylinder 19 moves, the exhaust oil flows through the normally-open solenoid-operated valve V2, on through-the line L3 and the fourway valve Fl and returns to the tank Tl.

As the piston in cylinder I9 moves, the drill advances at a given rate, as determined bythe pump, and comes into contact with the work.

The examples When the drill contacts the work, the pressure in the advance-side of the hydraulic system builds up because of the resistance to further movement of the drill l2, offered by the work I l. The pressure in line L5 increases and this increase in pressure actuates the pressure switch PSI.

The normally-open contact PS l-l, in the pressure switch PSI, closes and allows current to flow through coil R2-C on relay R2. This closes the contact R2-l and energizes the solenoids Sol VI, Sol V2, and Sol V3 on solenoid-operated valves Vl, V2, and V3 respectively. The normally-open valve VI closes. Now the only path of flow for the fluid going to the hydraulic cylinder is through needle valve NVI. Needle valve NVI regulates the flow of oil advancing the piston of the cylinder l9 and thus regulates the rate ofadvancement of the drill l2. Thus adjusting needle valve NVI gives the desired feedrate for'performing the work.

The normally-open solenoid-operated valve V2 closes and stops the flow of the exhaust fluid returning to the tank TI. The three-way valve V3 is of such an arrangement that the normal flow is from measuring cylinder Ml to tank Tl. When solenoid Sol V3 on valve V3 is energized the flow is from the line- Lt to said measuring cylinder Ml. Thus as the drill l2 advances and drills a hole, the exhaust oil from the cylinder l9 charges the measuring cylinder Ml.

The piston of MI rises and carries the arm 2i with it. As arm 2| rises and releases the plunger of limit switch LSI, thus operating said limit switch, the normally-open contact LS i-l, in said limit switch, is allowed to open, but since the contact Rll is-closed, coil RI-C on relay Rl remains energized.

The area of the measuring cylinder Ml is proportional to the area of the exhaust side of the cylinder [9. Thus the movement of the arm 2! is proportional to the movement of the drill l2. By making the area of the measuring cylinder Ml a small fraction of the area of the exhaust side of the cylinder l9, the arm ill moves in a magnified ratio to the drill ii, and the drill I2 is more accurately controlled.

The arm 2i rises until it actuates the limit switch LS2. This stops the further advancing of the drill l2 and retracts the drill l2 through the following described chain of actions. Limit switch LS2 operates and closes contact Elsi-i. This energizes coil RS-C on relay R3. The normally-closed contact R34 on relay R3 opens and deenergizes relay RI. The normally-closed contact R3-2 opens" and deenergizes relay R2.

The relay RI deenergizes and opens the contact Rl-Z. This deenergizes solenoid Sol Fl on four-way valve Fl. The flow pattern through valve Fl is reversed. The relay R22 deenergizes and opens contact R2-l. This deencrgizes solenoids Sol VI, Sol V2, and Sol V3 on valves V5, V2, and V3 respectively. The valves V l and V2, in their normal positions with their solenoids deenergized, are open and the hydraulic fluid flows to retract the piston in cylinder and us retract'the drill, at agiven rate, as determ by the pump. The normal position of the th way valve V3, with its solenoid Sol V3 dee gized, allows the hydraulic fluid to now from the measuring cylinder Ml to the tank TI. The spring around the piston rod in the measuring cylinder MI provides the force to discharge the said measuring cylinder and prepare it for its next measuring stroke.

The limit switch LS2 is adjustable relative to the limit switch LSI. Thus the length of the stroke of the measuring cylinder MI .is adjustable, and thus the drilling depth C of the hole in the work H is adjusted and controlled.

Another example of controlled measuredquantities of work is illustrated in Fig. 4. Here the work consists of moving the part 25 in a series of equally-spaced steps through the punch 26 and the die 21, in which manner a series of equally-spaced holes are punched in the part 25. To start the work, the part 25 is positioned for the first hole of the series. The pad 28 on the end of the piston rod 29 is brought to bear against the work 25, by manually bodily shifting the cylinder 30, its contained piston rod 29, and the pad 28. The punch press is started by any suitable conventional means, not shown, thus punching the first hole, and the switch SI!) in Fig. 6 is closed.

Limit switch LSM is positioned on the press so that contact LSM-I, on said switch, is closed when the punch is up. After punching the first hole, the press-ram rises, raising the punch, and limit switch LS'M is operated. Contact LSIA-I is closed. The normally-open contact LSI I-I on limit switch LSII is closed because the measuring cylinder MH is discharged. The current flows through the coil RI I-C on relay RI I.

The relay RII being energized closes the contact RI I-I and holds itself energized. The contact RI I2 closes and energizes solenoid Sol FI lA on four-way valve FII and solenoid Sol VI3 on three-way valve VIS.

The four-way valve FII is the spring-returnto-center type and is ported in such a manner that both lines LIZ and LI3 in Fig. 5 are blocked when the valve spool is in its central position. Energizing solenoid Sol FI IA on valve FII operates the valve so that the hydraulic fiuid flows from the pump P4 through the line LII to the line LI2.

The valve W2 is normally closed and no oil flows through line LI3 while the cylinder 30 is operating to space a series of holes.

The three-Way valve VI3 is arranged so that the normal flow is from the measuring cylinder MI I to the tank TII. However, as previously mentioned, the three-way valve VI3 was operated at the same time solenoid Sol Fl IA on valve FII was energized. And as the piston in the cylinder 30 advances, the exhaust oil flows to the measuring cylinder MI I.

In a manner similar to that described for the measuring cylinder MI shown in Fig. 2, the movement of arm 3| which is attached to the piston rod of the measuring cylinder MI I is proportional to the movement of the part 25. The position of the limit switch L812 relative to the limit switch LSII controls the spacing of the holes being punched in the part 25.

Limit switch LSI2 operates when the part 25 has been moved into position for the next hole to be punched. The contact LSI2-I closes and energizes coil RI3-C on relay-RI3. The normally-closed contact RI3-I opens to deenergize the relay RII. This deenergizes solenoid Sol FI IA on valve FII and allows the valve spool to return to its central position. Both lines LIZ and LI3 are blocked and the cylinder 30 is held locked in position.

Deenergizing the relay RII also deenergizes solenoid Sol Vl3 on three-way valve VI3. Valve VI3 returns to its normal position and allows the hydraulic fluid to flow from the measuring 6 cylinder MI I to the tank Tl I. The spring around the piston rod in the measuring cylinder Ml I provides the force to discharge the measuring cylinder MI I and prepare it for its next measuring stroke.

A contact, not shown, on relay Rlt controls the clutch of the punch press so that when the limit switch LSIZ operates the press is operated and the next hole is punched by the punch 25.

Then said press operates to raise punch 26, operate limit switch LSIA, and repeat the cycle. Thus aseries of holes continues to be punched until the limit switch LSI3 operates. The limit switch LSI3 is attached to the punch press in such a position that it operates after the last hole of the series to b punched in the part 25 is punched. Limit switch LSI3 operates to open contact LSI3-l and stop the repeating cycle.

The piston of the cylinder 30 is retracted to prepare it for the next series of spacings by closing switch SI I. This energizes coil REE-C on relay RIZ and closes contact RIZ-I. Current flowing through the contact RIZ-I energizes solenoid Sol FI IR on valve FH which changes the pattern of flow through valve FH so that the pump pressure is directed to line LE3, and line LIZ is open to the tank TI I.

The current flowing through the contact RI 2-! also energizes solenoid Sol W2 and opens the valve VIZ. This allows the hydraulic fluid to flow from line LI3 to the cylinder 38 thus retracting the piston rod 29 and the pad 28. After the cylinder 30 is in its retracted position, the switch SI I is opened.

Another example of controlled measuredquantities of work is shown in Fig. 7. Here the part is represented as being one of a series of tubular elements in which it is desired to machine a groove. The parts in the series vary in their inside diameter, but the depth D of the groove in each part must be identical. Again the approach-distance Varies.

The part is gripped in the chuck 33 by the jaws Q2. The chuck, rotating, causes the part lI to rotate. The tool 44, properly supported by parts not shown, is moved radially relative to the work 4|, by the piston rod 45 of the cylinder 46.

The steps in controlling the operation of machining the groove in the part M are identical to those described in connection with Fig, 1 fer drilling a hole a constant depth. The hydraulic equipment shown in Fig. 2 and the electrical arrangement shown in Fig. 3 illustrate the con trolling of this machining operation.

A more complex example of detecting when a quantity of work to be measured commences is illustrated in Fig. 8 and Fig. 9. These figures show a section through a tube M which is to be expanded into tight engagement in the tubehole 52 in the external element 53. The plane of the section in both figures is on the line 8-2 as shown in Fig. 10.

The expanding tool illustrated is the conventional cage-and-roller type using a tapered mandrel. The tapered mandrel 54 advances axially to move the rollers 55 outward radially to expand the tube. The segments of the cage 56 keep the rollers properly positioned.

A rolling force is applied on the tool While it is being expanded. This rolling force causes the rollers 55 to rotate, and as soon as the rollers make contact with the tube, the expanding-tool assembly rotates about the axis of the tapered mandrel.

Fig. 8 shows the mandrel 54 advanced to bring the rollers 55 into contact with the inner surface of the tube and it illustrates the conditions at the instant said rollers and cage are forced to revolve about the axis of the mandrel. Further advancing of tapered mandrel 54 moves rollers 55 outward radially and :distorts the tube.

The distorted tube has the general appearance of having bumps on its outer surface. These bumps roll about the periphery of the tube keeping their positions relative to the positionsof the rollers. And the bumps move outward radially as the mandrel advances and the rollers move outward.

It is evident, from Fig. 9, that as the bumps moving outward contact the surface of the tubehole they are restricted from further outward movement by the metal surrounding the tubehole. This additional resistance to the outward radial movement of said bumps produces a sharp increase in the magnitude of the force required to continue the outward radial movementof the rollers producing said bumps. Thus the instant when the several angularly spaced areas of the tube outer surface make firm contact with the surface of the tube-hole is accurately detected.

The continued outward radial movement of rollers 55, produced by the continued advancing of tapered mandrel 54, produces local compressive stresses, of a high magnitude, in the tubewall at the points wher the rollers contact said tube-wall, because of the reaction provided on the outer surface of said tube-wall by the resistance-to-movement of the metal surrounding the tube-hole. The metal in the tube-wall is thinned at the points Where said compressive stresses are produced.

As the above mentioned local compressive stresses are rolled around the periphery of the tube by the rolling action of the expanding tool, the tube-wall is thinned and the excess metal flows ahead of and in the direction of the rolling forces being applied, thus increasing the circumference and diameter of said tube. This thinning and enlarging action continues as long as said mandrel advances and said rolling action continues.

The effective work done on the tube portion being rolled is the work done while thinning and flowing the tube-wall to enlarge the tube circumference and bring said tube portion into tight engagement with its tube-hole. It is apparent that said effective work done on the tube portion is the quantity of work to be measured and that the true beginning point for this measured quantity of work is the instant when the several angularly spaced areas on the tube outer surface make firm contact with the surface of the tubehole.

This invention, by using a separate source of power to advance said tapered mandrel to thus force the rollers in said expanding tool to move outward radially, in which the magnitude of said mandrel-advancing force can be measured, provides a means for quickly expanding and distorting the tube and accurately determining the axial position of said mandrel and the corresponding radial position of said rollers at the instant said angularly spaced areas on the tube outer surface make firm contact with the surface of the tube-hole.

Since the radial movement of said rollers is proportional to the axial movement of said tapered mandrel, this invention, by measuring and controlling the amount of axial advancing movement of said tapered mandrel after the several angularly spaced areas on-the outer surface of the tube are in firm contact with the surface of the tube-hole and while the tube-wall is being thinned, provides a means for measuring and controlling the amount of the tube-wall thinning and its proportional enlarging of said tube portion.

Experiments have proven that this method of controlling the action of the expanding tool in which the rollers of said tool are radially expanded a controlled distance after the several angularly spaced areas on the tube outer surface are in firm contact with the surface of the tube-hole produces the correct amount of thinning of said tube-wall and enlarging of the circumference of said tube so that tube-joints are made uniformly tight regardless of the usual variations encountered in normal manufacturing practices. These usual variations are the variations in tube-hole size, tube 0. D., and tube-wall thickness.

Fig. 10 shows a machine for driving and controlling the expanding tool to perform the tube expanding operation by the method set forth in this'invention. Here the cage 5% and the rollers are shown in the tube 5| in the tube-sheet 53. The mandrel 554 is shown in its retracted position.

The cage 56 is confined in a rotatable manner in the thrust-sleeve 57 which confines a shoulder on the cage between a series of balls 58 and a lock-ring 59. The thrust-sleeve t! connects to a coupler 60 fastened to the front frame-member Si of the machine. Thus the cage-and-roller assembly is supported in a fixed axial position relative to the outer frame of the machine.

Part (-38 represents the power unit supplying the rotary force to the tapered mandrel 5d. The said rotary force is transmitted through the drive spindle 69. Spindle E9 is slidably supported in the frame-member ill. Power unit 66 is in slidable engagement with the outer frame of the machine.

Power unit 68 connects to the piston rod '15 of the hydraulic cylinder 67. Thus the tapered mandrel 54 is in a fixed axial relation with the piston "it of the cylinder 61, and the mandrel 54 moves with the piston ill.

The reaction on the cylinder 67 to the force applied on the piston ill is transmitted to the cage-and-roller assembly through the rear frame-member t2, the tie-rods 6366, the front frame-member Bl, the coupler 66 and the thrustsleeve 51. Thus the cage, and the rollers, of the expanding tool are in a fixed relation with the cylinder ti, and movement of the piston it relative to the cylinder $57 causes a like amount of axial movement between the rollers 55 and the tapered mandrel 54.

The section shown in Fig. 13, taken on the line !3l3 of Fig 10 shows how the tierods $5 and confine the lug l2 on the case of th power unit 88. Thus the reactive rotary force imposed on the case of the power unit 68' is transmitted to the outer frame of the machine.

The section shown in Fig. 14, taken on the line ldl4 of Fig. 10, shows the handles M and "it which the operator may use to hold the machine andresist the reactive rotary force. The lifting lug it may be attached to a supporting cable, not shown, and used to support-the machine.

The axial movements of the mandrel, as the machine expands a tube, may be powered and controlled with the arrangement of hydraulic components shown in Fig. 11. This arrangement of hydraulic elements is similar to that shown in Fig. 2 for controlling the drilling operation in Fig. 1.

The arrangement of the hydraulic components in Fig. 11 adds a solenoid-operated normallyopen valve V24 to the arrangement shown in Fig. 2. The schematic arrangement of the electrical equipment for controlling the hydraulic assembly shown in Fig. 11 has a time-delay relay TDI replacing the relay R3 shown in Fig. 3. These changes over the arrangement shown in Fig. 2 and Fig. 3 give a controlled dwell interval at the conclusion of the metal-thining work period being measured.

The dwell in this tube expanding-and-rolling cycle permits the rolling action to continue without any further outward radial movement of the rollers. Thus the metal-thinning action is allowed to gradually cease and the stresses around all parts of the periphery of the tubejoint are equalized before the expanding tool is retracted and withdrawn from the tube-joint.

The hydraulic fluid is pumped from tank T2I, in Fig. 11, to four-way valve F2I by pump PI I. Valve F2I is solenoid operated with the pressureflow from the pump through valve F2I and through normally-open valve V22 to the return connection on cylinder 67 when solenoid Sol F2I of said valve FZI is deenergized. Thus piston ID, of cylinder 51, and mandrel 54 of the expanding tool are normally held back in the retracted position.

The cycle is started by momentarily closing push-button switch BZI in Fig. 12. The controlcylindcr M23, which measures the further advance of the mandrel after the condition shown in Fig. 9 is established, is discharged and normallyopen contact LS2 i-i on limit switch LS2I is held closed. Thus when push-button B2I is closed, current flows through coil R2I-C on relay R2 I.

Contact RZI-l holds relay R2I closed. Contact R2I-2 energizes solenoid Sol F2I and actuates four-way valve F2I. Now the pressure-flow from pump Pi 5 goes through the advance side of the hydraulic circuit, through normally-open valve V24, and to the advance connection on cylinder 67. As piston III in cylinder 6'1 advances, the exhaust oil flows through normallyopen valve V22, through valve FZI, and back to tank T2 I.

As piston iii in cylinder 61 advances, mandrel 54 of the expanding tool advances at the given rate, as determined by the pump, and causes rollers 55 to move outward radially. As the mandrel advances, the expanding tool and the tube being rolled are relatively-quickly expanded through the condition shown in Fig. 8 to the condition shown in Fig. 9. At the instant the condition shown in Fig. 9 is established, the force required to continue the advance of the mandrel increases, as previously described, and the pressure in the advance-side of the hydraulic system increases and actuates pressure switch PSZI.

At this moment normally-open contact PSZI- I, in pressure switch PS2 I, closes and since contact RZI-S is being held closed, current flows through coil R22-C on relay R22. This closes contact R22-I and energizes the solenoids Sol V2I, Sol V722, and Sol V23 on the solenoid-operated valves VZI, V22, and V23 respectively. The normally-open valve V2I closes. Then the only path of flow for the fluid going to hydraulic cylinder El is through needle valve NV2I. Needle valve NV2I regulates the flow of oil advancing piston I0 of cylinder 61 and thus regulates the rate of advancement of mandrel 54 during the portion of the advance which produces the tube-wall thinning and its consequent tube-ens larging. Obviously, the preferred setting for NV2I is that which advances the mandrel, and thus expands the rolls, as fast as the metal thinning and flowing action can be performed. Thus the preferred setting for NVZI gives a mandreladvance rate proportional to the rate of plasticflow for the particular type of metal in the tubes being rolled.

Also at this instant, the normally-open solenoid-operated valve V22 closes and stops the flow of the exhaust fluid returning to tank T2 I. The three-way valve V23 is of such an arrangement that the normal flow is from measuring cylinder M23 to tank T2I. When solenoid Sol V23 on valve V23 is energized the flow is from cylinder 61 through the return circuit of the hydraulic system through valve V23 and to measuring cylinder M23. Thus as mandrel 54 advances and causes the expanding tool to thin and enlarge the tube, the exhaust fluid from cylinder 61 charges measuring cylinder M23.

The piston of M23 rises and carries arm 8I with it. Limit switch LS2I operates and opens normally-open contact LSZI-I, but since contact R2I-I is closed, coil R2I-C on relay RZI remains energized.

The area of measuring cylinder M23 is proportional to the area of the exhaust side of cylinder 61. Thus the movement of arm 8| is proportional to the movement of mandrel 54. By making the area of measuring cylinder M23 2. small fraction of the area of the exhaust side of cylinder 6?, arm 8| moves in a magnified ratio to mandrel 54, and the mandrel is more accurately controlled. This, of course, more accurately measures and controls the tube-wall thinning and tube-enlarging action of the tool.

Arm 8| rises until it actuates limit switch L822. This stops the further advancing of mandrel 54 through the following described series of actions. Limit switch LS22 operates and closes contact LS22-I. This energizes coil TDI-C on time-delay relay TDI, starting the time-delay interval. Contact LS22-2 closes and energizes solenoidSoZ V24 on solenoid-operated valve V24. Normally-open valve V24 closes. Thus the hydraulic fluid can no longer flow to cylinder 6?. The fluid between valve V24 and piston III! in cylinder 6'! is trapped.

As soon as limit switch L322 is actuated by arm 8|, the housing of said switch physically stops the further advancing of arm 8|, and the advancing of the piston in measuring cylinder M23 is stopped. Since the only path-of-fiow for the hydraulic fluid being exhausted from cylinder 61 is into measuring cylinder M23, the fluid on the exhaust side of the piston is trapped. The piston 10 of cylinder 61 is held in a fixed position, thus holding mandrel 54 in a fixed axial position. Thus, as previously described, the tube-wall thinning action is gradually stopped. This condition exists until the end of the timedelay interval. Then time-delay relay TDI acts and normally-closed contact TDI-I is opened.

When contact TDI-I opens, relay R2! is deenergized. Contact R2I-I opens. Contact R2I-2 opens and deenergizes four-way valve F2 I. The flow pattern through valve F2I is reversed. Contact R2 I-3 opens and deenergizes coil R2243 on relay R22. Contact R22-I opens and deenergizes the solenoids Sol V2I, Sol V22, and Sol V23 on valves V2l, V22, and V23 respectively. Valves V2l and V22, in their normal positions with their solenoids deenergized, are open so the hydraulic fluid may flow through them. The normal position of the three-way valve V23, with its solenoid deenergized, allows the hydraulic fluid to flow from measuring cylinder M33 to tank T2 l. The spring around the piston rod in measuring cylinder M23 provides the force to discharge said measuring cylinder and prepare it for its next measuring stroke.

As measuring cylinder M23 starts to discharge, arm 8! moves downward with the piston of said measuring cylinder. As arm Bl retracts, limit switch LS2; is released and contact LS32-2 opens to deenergize solenoid Sol V24 of valve VZ l. Valve V2 returns to its normally-open position and the hydraulic circuit is now open to allow piston "iii in cylinder 6? to retract, thus retracting the expanding tool. The automatic cycle of expanding and rolling a tube is completed.

Limit switch L822 is adjustable relative to limit switch LS2H. Thus the length of the stroke of measuringcylinder M23 is adjustable, and thus the amount of the tube-wall thinning and the tube enlarging is adjusted and controlled.

The handle 75, as shown in Fig. 14, on the frame of the expanding machine may be made to rotate with a switch for controlling the commencing of the expanding cycle mounted inside the rotating handle in such a manner that the cam action occurring when the handle 15 is rotated opens and closes the switch. Thus the handle '55 becomes a live-handle controlling the acting of the machine.

A second switch in the live handle 15, together with additional electrical components added to the electrical arrangement of Fig. 12, will provide a control for stopping the automatic cycle and retracting the expanding tool atthe will of the operator.

Another arrangement of the hydraulic elements for operating the machine shown in Fig. 10, is shown in Fig. 15. in this arrangement, the detecting of the beginning of the useful work to be measured is identical to that shown in Fig. 11, but the measuring of the useful work. is performed by a combined measuring and pressureboosting cylinder M33. The measured quantity of fluid is that being pumped into the hydraulic cylinder fill, of Fig. 10.

In the arrangement in Fig. 15, the pump PIE pumps the hydraulic fluid to the solenoid-operated four-way valve F35 through line L35. The solenoid operated valve F35 is a double two-way valve which is normally closed.

Closing the switch BM in Fig. 16 starts the cycle. Coil R3 l-C on relay RM is energized. The contact R3l-2 on relay R3l energizes solenoid Sol F3! on valve FM. The pressure-flow is now to line L32, through the check-valves CV2 and CV3 and on to the cylinder (5?, of Fig. 10.

The exhaust flow from the cylinder 6'? is through the check valve CV l, through line L33, and the four-way valve F3! to the tank T35. When the several angularly spaced areas on the tube outer surface make firm contact with the tube-hole, the pressure switch PS3! operates and closes contact PSSl-l. This energizes solenoid Sol F35 on valve F35 and allows flow to the booster-measuring cylinder M33.

The flow into the cylinder M33 is through the needle valve NV3I, which serves to regulate and control the rate of advancing of the booster cylinder and thus regulate and control the advance of the tapered mandrel 5 to give a rate suitable for thinning the tube metal. The flow entering the cylinder M33 causes the piston assembly to rise. Since the pressure is under the large-area piston, a proportionally higher pressure is hausted from the small-diameter cylinder into line L36.

This high-pressure in line L36 is blocked in the one direction by the check valve CV2. The only path of flow available is through the check valve CV3 and into cylinder 61. Arm 3| moves proportionally to piston It and the tapered mandrel li iof Fig. 10.

Limit switch L832 operates when the preselected amount of measured travel for the arm Si occurs. The contact LS32-I opens and deenergi solenoid Sol F35 on valve F33. Valve F35 closes and blocks both lines L3ll and L35 in the lowpressure compartment of the booster-measuring cylinder M33. The contact LS32-2 closes and actuates coil TD3IC on time-delay relay This gives a dwell during the time-dela interval. During the dwell, the tapered mandrel 54 is held in a fixed axial position. The rolling action continues and equalizes the stresses around the periphery of the tube-joint.

At the end of the time-delay interval the con tact TD 3l-l opens and deenergizes coil Bil-C on relay R3i. This deenergizes solenoid Sol on four-way valve F3! and reverses the flow through the valve. Another contact on the ti.-. 9 delay relay TD3I, not shown, opens the v F35 by energizing solenoid Sol F35 on valve l.

Needle valve NV32 serves as a restriction line.L33. Thus the flow goes to the boos" .7- measuring cylinder M33. The piston assembly in cylinder M33 retracts with the boostersure flow going to cylinder 6'5 through the check valve CV6.

The pressure and flow retracting the piston of cylinder 61 actuates the pilot-operated two-- way valve PVI and allows the oil being exhaus a? from cylinder 61 to flow direct to the tank After the measuring cylinder M33 is retracted. the fluid continues to flow to cylinder thro "h the needle valve'NV32. A time-delay relay, shown, operates to deenergize solenoid F301 F35 on valve F35, and the circuit is ready for the next cycle.

Fig. 17 illustrates another type of mechani 11, within the scope of this invention, which exp'iand rolls tubes into tight engagement in tubeholes. Here the detecting of the increase in force which indicates the commencing or" useful work is by mechanical means. And the preselected measuring and controlling of the displacement of the tool performing the work is by electro-mechanical means.

Another manner in which the machine shown in Fig. 1'7 differs from the one heretofore described is that the force advancing the tool to bring it into working position is applied only ing the approach-interval of the cycle. As soon as the useful work commences, the external force applied to advance the mandrel is dlSCODllliT and the power unit N58 is allowed to in axial direction while the self-feeding effect of a tool produces the additional expansion which thins and expands the tube into tight engagement in the tube-hole.

In this machine, the expander cage ifaii cor fines the rollers I55 at an axial-angle with axis of the tool. This gives the expanding tool a self-feeding effect in that the rotary force applied on the tapered mandrel lfi l together with the frictional-gripping of said tapered mandrel by the rollers I55 which is caused by the inward radial reactive force on the rollers, causes the tapered mandrel to screw itself into the assembly in much the same fashion as a woodscrew ad'- vances into wood. I

The expanding tool is connected to the front frame-member IIiI of the machine by the thrustsleeve I51 and the coupler ltd. The front framemember Isl is connected to the hydraulic cylinder I51 by the tie rods Its-455, and the rear frame-member I62.

The power unit I68 applies the rotary force to the tapered mandrel I 54 through the drive spindle I69. The power unit I68 is in slidable engagement with the outer frame assembly'and it is prevented from rotating in the outer frame by the lug I68, attached to the power-unit case, being confined between the tierods I65 and I56.

The force on the piston I19 of cylinder I51 causing the tapered mandrel Ifiito advance is transmitted to the power unit I68 through the thrust sleeve I11, the flange I16 and the spring I15. The rod I12 which is in slidable engagement with the thrust sleeve I1 I, piston I'IIB, thrust sleeve I11, and flange IN, is solidly connected to the case of the drive unit I58.

The rod I12 serves to guide this rear assembly, to guide the spring I15, and to provide vertical support for the drive unit I53. The sleeve Ill extending through the rear end of the cylinder I61 serves to bring the adjusting nut iisoutside of the hydraulic cylinder. 7

Turning the nut I13 on the rod I12 adjusts the preload in the spring I15. Thus spring I15 can be preloaded so that there is no decrease in length of the spring until the axial force onthe tapered mandrel I54 exceeds the preload setting. By setting the preload on the spring 15 and adjusting the screw I84, the machine isset to operate the limit switch LSAI at any selected force within the range of the spring. Thus the'increase in the linear force advancing said mandrel which occurs the instant the tube is expanded suflicient- 1y to bring several angularlyspaced areas of the outer surface of the tube into firm contact with the defining wall of its tube-hole is detected.

The adjusting screw I85 serves to prevent over travel which could damage limit switch LS H.

The housing IBB is in slidable engagement with the tierod IE3. The clamp pad I8I is enclosed in the housing Its in such a manner that when pad IBI is forced against tierod Hit, the housing I83 comes into fixed engagement with said tiered. .The solenoid I82 supplies the force for clamping the pad IBI to the tierod I63.

The guide-rod I19 is in siidable engagement with base member I15, attached to the case of power unit I63, and guide rod H9 is attached to housing I89. Thus the assembly of guide rod I19 and housing I80 forms a slide member slidable relative to tierod I63 or slidable relative to base member I16. Said slide member is normally pushed away from base member I16 by the compression spring I33 with such pushing-away movement being limitedby the flange I38 on guide red I 13. Thus in its normal condition, not clamped to tie rod I83, said slide member moves. relative to tierod I63, with base member I'lt. and power unit I68.

When the housing I89 is clamped to the tiered I63, base member I16 approaches the housing I89, compressing the spring I83, as mandrel Ii advances and pulls power unit IE3 forward. Thus the relative movement between base member I16 14 and said slide member is a measure of the man drel axial advancing movement. Limit switch LS42 is attached to base member I16. The adjusting screw I 81 forms an extension of the guiderod I19, and it is in line with the plunger on the limit switch L842.

After base member I16 moves relative to said slide member a sufficient amount, the screw I81 operates the limit switch L842. By controlling solenoid I82 so that it clamps said slide member to the tierod I63 at the instant the several angularly spaced areas on the outer surface of the tube are brought into firm contact with the defining surface of the tube-hole, the relative movement between the bracket I16 and the slide member serves to measure the advancement of the ta" pered mandrel I54 during the time the expand ing tool is thinning the tube wall.

An arrangement of hydraulic components which may be used to operate the machine shown in Fig. 17 is shown in Fig. 18. Here the solenoido'perated four-way valve FM is the spring-returnto-center type with the porting arranged so that when the valve spool is in its central position, both lines to the cylinder are open to the tank. Piston I10 in cylinder I61 is in a floating condition when valve FM is in neutral.

Pump PIG pumps the hydraulic fluid through line L4I to the four-way valve FM. Closing the switch B II energizes coil R4I-C on relay R II which in turn energizes solenoid Sol FAIA on valve FM. This operates the four-way valve so that the pressure-flow is through line Lei to line L42 and on to the cylinder I61. The tapered mandrel I54 advances.

The tapered mandrel I54 advances at a relatively rapid given rate until the several points on the outer surface of the tube contact the tubehole, as shown in Fig. 9, when the resistance to further advancing of the mandrel I54 increases. This increased resistance compresses spring I15 and operates the limit switch LS II. Obviously, the piston I10 must act to advance the mandrel at a rate faster than the mandrel is advanced by the self-feeding action of the tool in order to produce a linear force acting to compress the spring I15.

Limit switch LS4! operating, in turn energizes relay R42 and deenergizes solenoid Sol F iIA on. four-way valve FM. The valve spool in valve FM returns to center and allows piston HQ in cylinder I 61, the power unit I68, and the tapered mandrel I54 of Fig. 17, to float as a unit.

The relay R42 also energized the coil i82-C of solenoid I 82 on the clamp unit I863 so that the measuring of the additional advancementpi the tapered mandrel I54 commences.

The axial-power assembly being in av floating condition, the only advancement of the mandrel I 54 is that caused by the self-feeding effect of the expanding tool. The rotating force continues, and the expanding tool rotates and expands the tube, pulling the mandrel I54 forward and moving the limit switch L842 relative to the stop screw I81. I

The expanding action continues untilv the plunger on the limit switch L342 contacts the screw I81 and limit switch L842 operates. Then nut I13, rod I12, power unit [68, and drive spindle 159, transmits the retracting force to the-mandrel I54, pulls the mandrel back to retract the expanding tool and thus ends the expanding operation.

While, for the sake of illustration, the devices are herein shown and described in cormection with the performing of certain types of Work, it will be apparent to those skilled in the art that the principles of the invention may be applicable in other combinations in these same operations, and applicable in other operations and with Varioustypes of tools.

The hydraulic system in Fig. 10 and Fig. 17 may be replaced by some other type of power device such as the electric motor arrangement shown in Fig. 20. The mechanism shown in Fig. 20 is a duplicate of Fig. 17 with two exceptions. Fig. 20 shows an electric motor supplying the linear force advancing the mandrel, and it shows a hydraulic-powered clamp for clamping the measuring unit to the frame.

The electric motor 361 is attached to rear frame member [52 and positioned so that gear 316, on the shaft of said motor 361, makes proper engagement with gear-rack 311. Gear-rack 311 replaces thrust sleeve 511, and thrust sleeve 11!, of Fig. 1G, and, in an identical manner, transmits the force produced by motor 381. Rod 112, flange 114, and the other parts acting to transmit and control the linear forces moving the mandrel are as described for Fig. 17.

The hydraulic cylinder-and-piston assembly 382, in Fig. 20, replaces the solenoid 182, in Fig. 17. Pressure applied through line 389 produces a force acting on pad I81 to bring housing 130 into fixed engagement with tierod I 53 to thus cause the actions as described in connection with Fig. 17.

The energy-supply circuitry controlling the energizing of electric motor 361, in Fig. 20, acts identically to the hydraulic system energizing the hydraulic power device in Fig. 17 so that the apparatus of Fig. 20 performs in the same manner and produces the same results as are described for Fig. 1'1.

It is apparent that the increase in linear force axially advancing mandrel I54 which occurs the instant the tube portion is expanded suiiiciently to bring the several angularly spaced areas of the tube outer surface into firm contact with the defining wall of its tube-hle, and which com.- presses spring 115, also increases the energyinput demanded by electric motor 351. Thus it is apparent that the increase in linear force sensed by the force-sensitive device illustrated in Fig. 20 could be equally sensed by a conventional current-sensitive device connected into the electrical circuit to motor 361, and set to be actuated when the proper current value is developed, and whereby, when actuated, said currentsensitive device performs functions similar to those performed by switch LSIH, of Fig. 17.

Another arrangement of apparatus, within the scope of this invention, is illustrated in Fig. 21. mechanism is identical to that shown in Fig. 10, except that, in Fig. 21, the roll-cage 56, of 10, is power rotated and, therefore, the power unit 63, of Fig. 10, remains in a fixed axial position, relative to said roll-cage and the apparatus frame.

The mechanism shown in Fig. 21 has a power unit 358 transmitting the rotary force to rollcage 353 by means of drive spindle 369. Power unit 368 is attached to front frame-member Bl,

16 and roll-cage 35B is connected to drive spindle 369, thus supporting the cage-and-roller assembly in a fixed axial position relative to the apparatusframe while said cage is being power rotated.

In Fig. 10, the thrust reactionbetween the mandred and roll-cage produced by the linear force being applied, is transmitted to frame mem ber 61 by means of bearing 58, thrust-sleeve 51, and coupler 60. The said thrust reaction, in Fig. 21, is transmitted to frame 6| by means of drive spindle 369, the bearings in power unit 368, which support spindle 369, the case of power unit 368 and. the connecting means attaching said power unit to frame member 6 l.

The mandrel 54, in Fig. 21, connects directly to piston rod 31! with piston rod 31! axially sliding through hollow sleeve-like spindle 359 and through the suitable opening provided in the case of power unit 368.

The power-rotated roll-cage 356 acts to push the rolls by means of the contact surface of the ligaments of said roll-cage bearing against said rolls, to thus rotate said rolls about mandrel 54. As the rolls rotate about said mandrel, they are in contact with the surface of the mandrel and the inner surface of the tube portion being expanded and the relative movement between the rolls and said surfaces is partly rolling and partly sliding.

The circuitry used to power and control the mechanism shown in Fig. 10, as shown in Fig. 11 and Fig, 12, can be used to power and control the mechanism shown in Fig. 21. The actions and results obtained when said circuitry operates the Fig. 21 mechanism are as described for Fig. 10.

While the invention hasbeen described with reference to the particular devices illustrated, it is to be appreciated that it is not so limited. It is rather of a scope commensurate with the scope of the subjoined claims.

What I claim as my invention is:

1. An apparatus for expanding a lineal portion of a tube, to a preselected tightness, in its tubehole, comprising a roller-type expanding tool having a roll-cage, a plurality of angularly spaced expanding-rolls radially movable in the roll-cage, with said roll-cage and said expanding-rolls rotatably mounted about a tapered, axially movable, mandrel; a frame to which said roll-cage is rotatably connected, a powered tool-rotatin unit carried by the frame, a power device adapted to produce a linear force acting to advance the mandrel axially, at a given rate, the power device producing the linear force being so connected to said frame that the reaction to the linear force advancing the mandrel is resisted by said frame, a force-sensitive device actuated by the increase in the linear force axially advancing the mandrel which occurs the instant the tube portion is expanded sufiiciently to bring several angularly spaced areas of the tube outer surface into firm contact with the defining wall of its tube-hole, thus detecting the start of the tube-wall thinning action, a measuring device started into actuation by the force-sensitive device at the instant of such detection and which, by its actuation, measures the further axial advancing movement of the mandrel, and means responsive to the measuring device and acting to limit said further axial advancing movement of the mandrel whereby the tube wall is thinned a preselected measured amount and said portion of the tube is circumferentially enlarged sufliciently to give it the preselected tightness in its tube-hole.

2. An apparatus as in claim 1; wherein said last named means'subsequently acts to cause the application of a linear force axially retracting said mandrel.

3. An apparatus as in claim 1; including means responsive to said measuring device and applying a linear force axially retracting said mandrel after the tube portion is so enlarged.

' 4. An apparatus as in claim 1; including means responsive to said measuring device, acting after the tube portion is so enlarged, continuing the rolling action with no change in axial position of said mandrel for a controlled interval of time, and thereafter applying a linear forceaxially retracting said mandrel.

5. An apparatus as in claim 1; including means actuated by said force-sensitive device at the instant of such detection and operable to'regulate the rate of mandrel advance during its said further axial advancing movement.

6. An apparatus as in claim 1; wherein said given rate of axial advancing of the mandrel is relatively rapid, and wherein there in included means actuated by said force-sensitive device at the instant of such detection and operable to decrease the rate of mandrel advance during its said further axial advancing movement.

'7. An apparatus as in claim 1; wherein said power device is an hydraulic cylinder'and-piston motor mounted on said frame.

8. An apparatus as in claim 7; wherein said hydraulic motor responds to said measuring device, after the tube portion is so enlarged, in a manner to apply a linear force axially retracting said mandrel.

9. An apparatus as in claim '7; wherein said hydraulic motor responds to said measuring device, after the tube portion is so enlarged, and

after the rolling action is continued with no change in axial position of said mandrel for a controlled interval of time, in a manner to apply a linear force axially retracting said mandrel.

10. An apparatus as in claim 1; wherein at least some of said rolls are cooked to effect a self-feeding of the mandrel, and wherein there is included means actuated by said force-sensitive device at the instant of such detection and operable to deenergize said power device whereby the self-feeding action of said tool produces said further axial advancing movement of the mandrel.

11. An apparatus as in claim 10; wherein said power device is an hydraulic cylinder-and-piston motor mounted on said frame.

12. An apparatus for expanding a lineal portion of a tube, to a preselected tightness, in its tube-hole, comprising a roller-type expanding tool having a roll-cage, a plurality of angularly spaced expanding-rolls radially movable in the roll-cage, with said roll-cage and said expanding-rolls rotatably mounted about a tapered, rotatable and axially movable, mandrel; a frame to which said roll-cage is rotatably connected, a powered tool-rotating unit for rotating the mandrel and having an element axially movable with said mandrel, said unit carried by the frame, a power device adapted to produce a linear force transmitted by means of said element to advance said mandrel axially, at a given rate, the power device producing the linear force being so connected to said frame that the reaction to the linear force advancing the mandrel is resisted by said frame, a force-sensitive device actuated by the increase in the linear force axially advancing the mandrel which occurs the instant the tube portion is expanded sufliciently to bring several angularly spaced areas of the tube outer surface into firm contact with the defining wall of its tube-hole, thus de-, tecting the start of the tube-wall thinning action, a measuring device started into actuation by the force-sensitive device at the instant of such detection and which, by its actuation measures-the further axial advancing movement of the mandrel, and means responsive to the measuring device and acting to limit said further axial advancing movement of the mandrel whereby the tube wall is thinned a preselected measured amount and said portion of the tube is circumferentially enlarged sufficiently to give it the preselected tightness in its tube-hole.

13. An apparatus for expanding a linealportion of a tube, to a preselected tightness, in its tube-hole, comprising a roller-type expanding tool having a roll-cage, a plurality of angularly spaced expanding-rolls radially movable in the roll-cage, with said roll-cage and said expanding-rolls rotatablymounted about atapered, non-rotatable andaxially movable, mandrel; a frame to which said roll-cage is rotatably connected, a powered tool-rotating unit for rotating the roll-cage, said unit carried by the frame, a power device adapted to produce a linear force acting to advance the mandrel axially, at a given rate, the power device producing the linear force being so connected to said frame that the reaction to the linear form advancing the mandrel is resisted by said frame, a force-sensitive device actuated by the increase in the linear force axially advancing the mandrel which occurs the instant the tube portion is expanded sufficiently to bring several angularly spaced areas of the tube outer surface into firm contact with the defining wall of its tube-hole, thus detecting the start of the tube-wall thinning action, a measuring device started into actuation by the force-sensitive device at the instant of such detection and which, by its actuation, measures the further axial advancing movement of the mandrel, and means responsive to the measuring device and acting to limit said further axial advancing movement of 'the mandrel whereby the tube wall is thinned a preselected measured amount and said portion of the tube is circumferentially enlarged sufiiciently to give it the preselected tightness in its tube-hole.

14. An apparatus for expanding a lineal portion of a tube, to a preselected tightness, in its tube-hole, comprising a roller-type expanding tool having a roll-cage, a plurality of angularly spaced expanding-rolls radially movable in the roll-cage, with said roll-cage and said expand ing-rolls rotatably mounted about a tapered, rotatable and axially movable, mandrel; a frame towhich said roll-cage is rotatably connected, a powered tool-rotating unit for rotating the mandrel and having an element axially movable with said mandrel, said unit carried by the frame, a hydraulic cylinder-and-piston motor adapted to produce a linear force transmitted by means of said element to advance said mandrel axially, ata given rate, the hydraulic motor being so connected to said frame that the reaction to the linear force advancing the mandrel is resisted by said frame, a measuring device comprising a cylinder-and-piston assembly and an electrical switch attached to the cylinder with the switch arranged so as to be operated when the piston hasmoved, relative to said cylinder, to advance a preselected distance, with said switch, when operated, causing an action whereby the mandrel advancing movement is limited, said measuring device being connected into the fluid circuit for said hydraulic motor so that the fluid discharged from said motor when its acts to axially-advance said mandrel is directable to said measuring device'to produce an advancing movement of said measuringdevice piston which is proportional to the advancing movement of said mandrel to thus measure the axial advancing movement of said mandrel, a force-sensitive device consisting of a pressure-actuated switch arranged so as to be responsive to thefluid pressure acting on said hydraulic motor to produce the mandrel-advancing movement, with said switch operating, when the force-sensitive deviceis actuated, to actuate means whereby said measuringdevice is started into actuation, with said force-sensitive device being actuated by'the increase in said fluid pressure producing the linear force advancing the mandrel which occurs the instant the tubeportion is expanded sumciently to bring several angularly spaced areas of the tube outer surface into firm contact with the defining-wall of its tube-hole, thus detecting the start of the tube-wall thinning action, means actuated by the'force-sensitive device at the instant of such detection and regulating the rateof advancing of said mandrel during its 'further advancing movement, and means responsive to the measuring device and acting to limit said further axial advancing -movement of the mandrel whereby the tube wall is thinned a preselected measured amount and said portion of the tube is circumferentially enlarged 'sufiiciently to give it the preselected tightness in its tube-hole.

15. An apparatus as in claim 14; including means responsive to'sai'd measuring device, acting after the tube portion is so enlarged, and powering said hydraulic motor to produce a linearforce axially retracting said-mandrel.

'16. An apparatusas'in claim 14; wherein said hydraulic motor responds to said measuring device, after the tube portion is so enlarged, and

after the rolling action is continued with no change in axial position of saidmandrel for a controlled interval of time, in a manner to apply a linear force axially retracting said mandrel.

17. An apparatus for expanding a lineal portion of a tube, to a preselected tightness, in its tube-hole, comprising a-roller-type expanding tool having a roll-cage, "aplurality of angularly spaced expanding-rolls radially movable in the roll-cage, with said roll-cage and said expanding-rolls rotatably mounted about a "tapered, rotatable and axially movable, mandrel; a frame to which said roll-cage is rotatably connected, a powered tool-rotating unit for retating the mandrel and having an element axially movable with'said mandreLsaid unit carried by the frame, a hydrauliccylinder-and-piston motor adapted to produce a linear force transmitted by means of said element to advance said mandrel axially, at a given rate, the hydraulicamotor beingso connected to said 'frame that the reaction to the linear force advancing the mandrel is resisted by said frame, a-measuring device comprising a cylinder-and-piston assembly and an-electrical switch attachedto the cylinder with the switch aranged so as to be operated when the piston has moved, relative to said cylinder, to advance a preselected distance,

with-said switch when operated, causing an :action whereby the mandrel advancing movement is limited, said measuring device being connected into the fluid circuit for said hydraulic'motor so that the fluid discharged from the cylinder of said measuring device, when its piston advances, powers said hydraulic motor to produce a proportional advancing movement of said mandrel to thus provide a measure of the axial advancing movement of said mandrel, a force-sensitive device consisting of a pressure-actuated switch arranged so as to be responsive to the fluid pressure acting on said hydraulic motor to produce the mandrel-advancing movement, with said switch operating, when the force-sensitive device is actuated, to actuate means whereby said measuring device is started into actuation, with said force-sensitive device being actuated by the increase in said fluid pressure producing the linear force advancing the mandrel which occurs the instant the tube portion is expanded sufliciently to bring several angularly spaced areas of the tube outer surface into firm contact with the defining wall of its tube-hole, thus detecting the start of the tube-wall thinning action, means actuated by the force-sensitive device at the instant of such detection and regulating the rate of advancing of said mandrel during its further advancing movement, and means responsive to the measuring device and acting to limit said further axial advancing movement of the mandrel whereby the tube wall is thinned a preselected measured amount and said portion. of the tube is circumierentially enlarged sulficiently to give it the preselected tightness in its tube-hole.

18. An apparatus for expanding a lineal portion of a tube, to a preselected tightness, in its tube-hole, comprising a roller-type expanding tool having a roll-cage, a plurality of angularly spaced expanding-rolls radially movable in the roll-cage, with said roll-cage and said expanding-rolls rotatably mounted about a tapered, rotatable and axially movable, mandrel, with at least some of said rolls cooked to efiect a selffeeding of the mandrel; a frame to which said roll-cage is rotatably connected, a powered toolrotating unit for rotating the mandrel and having an element axially movable with said mandrel, said unit carried by the frame, a power device adapted to produce a linear force transmitted by means of said element to advance said mandrel axially, at a given rate, the power device producing the linear force being so connected to said frame that the reaction to the linear force advancing the mandrel is resisted by said frame, a measuring device comprising a base member attached to said element, a slide member resiliently slidable relative to the base member and slidably coordinated with said apparatus frame, an electrical switch attached to said base member so as to be operated when said base member has advanced, relative to said slide member, a preselected measured distance, with said switch, when operated, causing an action whereby the mandrel advancing movement is limited, and a powered clamp attached to said slide member so that, when actuated, it clamps said slide member to said frame to produce a relative advancing movement between said base member, advancing with said element, and said slide member which is a measure of the advancing movement of said mandrel, a force-sensitive device having a resilient member connected to said element so that said linear force advancing said mandrel acts on the resilient member, and an electrical switch which, when operated, actuates means whereby said powered clamp is actuated, with said switch arranged in combination with said resilient member and said element so that the increase in the linear force advancing said mandrel which occurs the instant the tube portion is expanded sufficiently to bring several angularly spaced areas of the tube outer surface into firm contact with the defining wall of its tube-hole causes the resilient member to actuate said electrical switch, thus detecting the start of the tube-wall thinning action, means actuated by the force-sensitive device at the instant of such detection and operable to deenergize said power device whereby the selffeeding action of said tool produces the further axial advancing movement of said mandrel, and means responsive vto the measuring device and acting to limit said further axial advancing movement of the mandrel whereby the tube wall is thinned a preselected measured amount and said portion of the tube is circumferentially enlarged sufiiciently to give it the preselected tightness in its tube-hole, and to thereafter energize said power device to produce a linear force axially retracting said mandrel.

19. An apparatus as in claim 18; wherein said power device is an hydraulic cylinder-and-piston motor mounted on said frame.

20. An apparatus for expanding a lineal portion of a tube, to a preselected tightness, in its tube-hole, comprising a roller-type expanding tool having a roll-cage, a plurality of angularly spaced expanding-rolls radially movable in the roll-cage, with said roll-cage and said expanding-rolls rotatably mounted about a tapered, non-rotatable and axially movable, mandrel; a frame to which said roll-cage is rotatably connected, a powered tool-rotating unit for rotating the roll-cage, said unit carried by the frame, a hydraulic cylinder-and-piston motor adapted to produce a linear force acting to advance the mandrel axially, at a given rate, the hydraulic motor being so connected to said frame that the reaction to the linear force advancing the mandrel is resisted by said frame, a measuring device comprising a cylinder-and-piston assembly and an electrical switch attached to the cylinder with the switch arranged so as to be operated when the piston has moved, relative to said cylinder, to advance a preselected distance, with said switch, when operated, causing an action whereby the mandrel advancing move ment is limited, said measuring device being connected into the fluid circuit for said hydraulic motor so that the fluid discharged from said motor when it acts to axially-advance said mandrel is directable to said measuring device to produce an advancing movement of said measuring-device piston which is proportional to the advancing movement of said mandrel to thus measure the axial advancing movement of said mandrel, a force-sensitive device consisting of a pressureactuated switch arranged so as to be responsive to the fluid pressure acting on said hydraulic motor to produce the mandrel-advancing movement, with said switch operating, when the force-sensitive device is actuated, to actuate means whereby said measuring device is started into actuation, with said force-sensitive device being actuated by the increase in said fluid pressure producing the linear force advancing the mandrel which occurs the instant the tube portion is expanded sufliciently to bring several angularly spaced areas of the tube outer surface into firm contact with the defining wall of its tube-hole, thus detecting the start of the tubewall thinning action, means actuated by the force-sensitive device at the instant of such detection and regulating the rate of advancing of said mandrel during its further advancing movement, and means responsive to the measuring device and acting to limit said-further axial advancing movement of the mandrel whereby the tube wall is thinned a preselected measured amount and said portion of the tube is circumferentially enlarged sufiiciently to give it the preselected tightness in its tube-hole.

21. The method of applying and controlling a progressively-applied rolling pressure, acting simultaneously on several angularly spaced areas of the inner surface of a lineal portion of a tube, so that the rolling pressure acts to thin the tube wall a preselected measured amount and thus circumferentially enlarge said portion of the tube to give it a preselected tightness in its tubehole, which comprises applying, at a given rate, a torsional force to produce the rotating-force component of said rolling pressure, applying, at a given rate, a separate linear force, acting axially relative to said tube, transmitted by means developing a proportional normal component to produce the radial-force component of said rolling pressure, detecting the increase in the linear force, producing the increase in said radial-force component of said rolling pressure, which occurs the instant the tube portion is expanded sufliciently to bring several angularly spaced areas of the tube outer surface into firm contact with the defining wall of its tube-hole, and then measuring and limiting the further displacement of said linear force which thus measures and limits the proportional further displacement of said radial-force component of said rolling pressure whereby said tube Wall is thinned the preselected measured amount.

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